The overall aim of the proposed research is to find possible relationships between the methylation of nuclear proteins and growth of tissues, with the following objectives: (1) To investigate the possible relationship between the extent of methylation of nuclear proteins (particularly histones) and the degree of differentiation and rate of growth of neoplastic tissues. (2) to study the levels of various histone methylating and demethylating enzymes during liver regeneration and growth of neoplasms.